The present invention relates to an evacuation apparatus and, more particularly, to safety equipment used on the ground level for catching evacuees who are forced to leap from the upper floors of burning multistoried buildings or from other high levels in disaster areas where the normal escape routes or fire exits have been made inaccessible or dangerously impracticable due to the prevailing conditions of the disaster, be it fire, earthquake, or such.
The most commonly used device for retrieving leaping evacuees at a fire disaster site has been the firemen's net, a large circular frame having a flexible fabric lashed therein. This retrieval net requires the strength of six or more persons to hold it suspended above the ground level in the proximity of the leaping fire victims. As can be envisioned, this form of retrieval net, being at least 15 feet in diameter, is unwieldy and awkward to transport to and from the disaster site.
An even more significant limitation of such nets, however, is their inability to provide sufficient cushioning to permit safe jumps from elevations of several stories, such that they are substantially useless for aiding fire victims in high rise buildings.
More recent patents in the art of retrieving falling objects by means of air cushions are cited as follows: Mapes, U.S. Pat. No. 2,906,366 for a Body Catcher; Mitchell and Rollings, U.S. Pat. No. 2,840,194 for a Shock-Absorbing Air Cushion; Warden, U.S. Pat. No. 2,721,048 for a Shock Absorber for Parachute Drops; Stanley, U.S. Pat. No. 2,712,913 for Aerial Drop Equipment; and Frost, U.S. Pat. No. 3,250,065 for a Decelerating Catcher for Moving Objects.
The latter Frost patent, in an alternate fourth form, describes a mobile vehicle comprising a metal chassis or frame upon which is attached a flexible membrane which can be inflated by a pressurizing fluid to form a cushion for catching falling bodies. This cushion has a plurality of orifices which permit a controlled continuous escape of the pressure fluid from the air chamber. The Frost device, when impacted, exhausts a large amount of air to the atmosphere through a controlling orifice to absorb the momentum of the falling object. This air must be replaced by a pump, often requiring 15-25 seconds, before the unit becomes operable for absorbing the momentum of a successive impact. Even though the apparatus seems to be mobile, the heavy chassis mounted on wheels must be towed to its operational site and carefully maneuvered into place.
Other shock-absorbing devices, such as disclosed in the Mitchell/Rollings or the Warden patents, are primarily used for protecting loads dropped from airplanes, with or without the means of a parachute. Each device is equipped with a pressure relief valve or orifice located in its exterior wall that automatically opens when the device is impacted upon reaching the ground, thus partially deflating said device to absorb the momentum of the impact. No means for restoring the air pressure is provided.